Slidable doors which are suspended for displacement on top support rails in order to close a door opening of a refrigeration housing are known, such as disclosed in U.S. Pat. Nos. 4,476,652 and 4,680,828, as examples thereof. In such known designs the door is displaced to seal about a door opening frame. A displaceable support mechanism is usually provided between the top edge of the door and the horizontal support rail to cause the door to move against the door opening. Also, the bottom of the door is usually guided by rollers or other type of guide assemblies secured to the floor, such as disclosed in the above-referenced prior art patents. As disclosed in such prior art, the top support mechanism is somewhat complex and periodically requires repair and adjustment which is difficult due to their construction and location inside the top rail with the load of the door being applied thereto. Also, some of the guide mechanisms in the bottom edge of the door are sometimes difficult to engage with the bottom of the door which is displaced out of engagement thereof.